1. Field of the Invention
This invention relates to apparatus for receiving a film cassette containing therein a roll of exposed 35 mm instant film preparatory to processing the exposed film in the apparatus.
2. Description of the Prior Art
The present invention relates to apparatus for processing an exposed roll of film and, more particularly, to apparatus for processing an exposed roll of 35 mm self-developing or instant type transparency film.
One such type of apparatus is described in U.S. Pat. No. 2,880,657 wherein a camera-projector is provided with means for processing an exposed photosensitive sheet by superposing the photosensitive sheet with a second sheet and spreading a thin layer of processing composition between the superposed sheets as they are being wound upon a rotating drum. The photosensitive and second sheets are maintained upon the drum in superposition with the layer of processing composition interposed therebetween for a predetermined processing period during which visible images are produced in one of the sheets, preferably in the second sheet. At the end of this predetermined period of time, the second sheet is stripped from the photosensitive sheet, advanced past a projector such that the images therein may be viewed, and then wound upon a take-up spool. However, this apparatus does not lend itself to the processing of 35 mm instant type film, which film is packed in a cylindrically shaped 35 mm type film cassette which is adapted to be exposed outside the processing apparatus, i.e., in conventional 35 mm cameras.
Lately, interest has been expressed in providing a film assemblage wherein a roll of 35 mm instant type film is housed within a film cassette having a configuration whereby it is readily adapted to be mounted within conventional 35 mm cameras, e.g., a Minox 35 EL, manufactured by Minox GmbH of Lahnstadt 1, West Germany. As such, these film assemblages release the conventional 35 mm camera from their time long restraint, i.e., use with conventional film only. Examples of these film assemblages may be found in U.S. Pat. Nos. 4,212,527 and 4,167,318 and in pages 132-134 of Research Disclosure dated April, 1980.
The film assemblages disclosed in the RESEARCH DISCLOSURE article basically include a cylindrically shaped film cassette of the type adapted to be received within conventional 35 mm cameras, a supply of film, and processing composition located within the film cassette. The film in these assemblages is adapted to be processed in the camera in which the film was exposed. After the film has been almost totally withdrawn from the film cassette during the exposure thereof, it is rewound into the film cassette and during such rewinding, a container (or a plurality of containers) of the processing composition is ruptured by a lip located adjacent to the film withdrawal slot in the cassette and its contents spread between superposed sheets of the film. Disadvantages with these types of film assemblages are many and include (1) a limit on the length of film that may be wound within the film cassette due to the volume occupied by the processing composition, and (2) the shelf life of the assemblage is a function of the shelf life of the film or that of the processing liquid, whichever is the shorter, vis-a-vis an assemblage which does not contain the processing composition as a part thereof.
Each of the film assemblages disclosed in the aforementioned U.S. Pat. Nos. 4,212,527 and 4,167,318 is adapted to be placed in apparatus for processing the exposed film. The apparatus described in U.S. Pat. No. 4,212,527 includes an extendible dark chamber for receiving the exposed film after it has been treated with a processing composition, thereby adding to its cost and overall size. The apparatus described in U.S. Pat. No. 4,167,318 is rather large in comparison to the size of the film cassette used therein; and its operation includes the complete removal of the exposed film from the film cassette before it can be processed, a step which adds to the cost of the apparatus due to the control circuit which must be built into the apparatus to detect the presence of the trailing end of the exposed film and its associated container of processing composition.
From the above, it can be seen that there is a need for a small compact apparatus for processing a roll of exposed 35 mm instant type film. The apparatus should include means for housing and thereafter superposing a second sheet with the exposed sheet of film so as to facilitate the formation of visible images in one of the two sheets, preferably in the sheet of film, thereby enabling a greater length of film to be originally coiled within the film cassette. Further, the apparatus should be provided with means for stripping the film from the second sheet while the former is being simultaneously guided to the exterior of the apparatus.